Changing times

Australia's animals and plants are already reacting to climate change. Fairy penguins are breeding earlier, gum trees are flowering at different times and birds are migrating prematurely. There's something afoot in the world of nature: the times really are a-changing!

Cicadas seem to be hanging around until later in the year. (Source: Keith Power)

In recent years, many people have noticed that weird things are happening. Cicadas seem to be around later. 'Spring' bulbs are flowering in the middle of winter. Some bird species are nesting months earlier than they did a decade ago. Spiders are still lurking in their webs well into autumn, when most would normally have died off. What's going on?

Scribbly Gum decided to investigate whether plants and animals in Australia are already feeling the effects of climate change. The first thing we wanted to know was what you have noticed. We invited you to submit your observations on any changes you've noticed during the past 5-20 years in your own backyard or neighbourhood. In the past month we've received over 60 reports from almost every state and territory.

The proof is in the scientific pudding

There are less frogs seen in both Victoria and Western Australia.
(Source: Tim Hoffman)

So what do these results prove? Well, they are anecdotal, so from a scientific view they can't be counted as statistically significant. But they do suggest some trends. Generally people reported that there are fewer frosts and less snow, rainfall has dropped in some areas and the soil is drying out. Many birds are appearing where they haven't been seen before, and some are nesting earlier. Frogs and bluetongue lizards are declining in some areas.

But are these changes due to climate change, or perhaps just a bad drought?

One of the problems with working out whether climate change is affecting Australia's biodiversity is that we haven't really been keeping records for that long, says Professor Hugh Possingham. Possingham is Professor of Ecology at the University of Queensland and chaired a Federal Government workshop on the issue in 2002.

"Britain has a tradition of natural history study, and both Britain and Europe have bird counts going back 40 to 50 years", he says. Australian research, by contrast, has specialised in spatial rather than temporal ecology because of the sheer size of our continent. Our weather cycles are also very different. Because of the 6-10 year effect of El Nino, we need to track any changes through at least three to four of these cycles (say 40 years) to be sure we are looking at a long term change, he says.

Fact file:

When: The past 20 years

Where: Across Australia

Other info: CSIRO predicts that Australia's average annual temperature will increase between 1-6 degrees C in the next 60 years. Since 1910, Australia's average temperature has increased 0.7 degrees C, mostly since the 1950s, and 1998 was the warmest year on record.

Climate change and biodiversity was the cover story in the prestigious Nature magazine in January last year. The story reported on new research showing that 15-37% of a sample of 1,103 land plants and animals would eventually become extinct as a result of the climate changes expected by 2050. For some of these species there will no longer be anywhere suitable to live. Others will be unable to reach places where the climate is suitable. The story added that a rapid shift to technologies that do not produce greenhouse gases, combined with carbon sequestration, could save 15-20% of species from extinction.

Australia slow to show impacts

Britain and Europe have already recorded many examples of butterflies and birds expanding their ranges, almost certainly in response to climate change (for example, it is warmer, further north than it used to be, making it more comfortable for many insects).

But unlike these places, which have a dependable rainfall pattern and seasonal cycle, Australia's climate is characterised by prolonged periods of drought and erratic rainfall. Ecologist Dan Lunney from the Department of Environment and Conservation NSW says it is for this reason that it may take a lot longer to observe the impacts of climate change on biodiversity here.

"The effects [of climate change] will take longer to manifest in Australia because our animals are already adapted to fire and drought … ducks can fly, frogs can remain dormant, but they can only do it for so long. Australian animals in a sense are buffered. But by the time we do see changes, we'll be wringing our hands."

Added to this are pressures from logging and land-clearing for agriculture and urban development. These activities displace animals and plants from their normal habitat and make it difficult for them to move into new areas. "Climate change mightn't matter as much in a very large pristine area, but when you've got land clearing or logging as well, it becomes a cumulative effect", says Lunney.

When the birds arrive

In The New Nature, Australian biologist Tim Low describes how the naturalist John Gilbert was hired by John Gould to find new birds in south-west Australia during early settlement days.

"Today, the observations he [Gilbert] made are remarkable for what they don't say", writes Low. Gilbert's bird list, says Low, doesn't include some of the most common birds found in Perth today — such as spoonbills, ibises, galahs and crested grebes. In fact, 14 bird species have moved in to the area since Gilbert was there in the mid 1880's.

What does this mean? For one, it says that birds, being highly mobile, don't hesitate to shift to new areas that suit their needs. But what if this movement were to be caused, not by the lure of human settlement and the food it offers, but by an urgent need to escape from an area that has become unliveable for a species because of the effects of climate change?

Some Australian researchers already have strong evidence that climate change is affecting wildlife. Dr Lesley Hughes and her students from Macquarie University have been combing old bird club journals for useful data. The journals go back to the 1960s, and so represent a relatively long record.

They have been compiling a list of 'first sightings', the date when a certain bird arrives or is 'seen' for the first time that year. They've discovered that birds are arriving three and a half days earlier per decade, showing there is a change in bird behaviour that is probably too long term to be accounted for by a drought alone.

Several well known birds species have expanded their range south according to Julian Reid from CSIRO. These include the Figbird, Channel-billed Cuckoo, Common Koel and the Australian Brush Turkey.

"Things are shifting much faster than we would have predicated," says Hughes. "If we are seeing these sorts of shifts with just a 0.7 degree change in temperature, imagine what would happen with a 5 degree change over the next hundred years?"

Flying fox range contracting

The migration of the flying fox could be an indication of climate change.
(Source: Kevin Tait)

Another possible early indicator of climate change is the flying fox, which formerly had a northern distribution. Research by Dr Chris Tidemann from the Australian National University has shown that the grey-headed flying fox has contracted its range south from its northern boundary by 750km since the 1930s. No one knows exactly why.

Animals in the Alps moving higher

Meanwhile, in the Australian Alps, Ken Green from Department of Environment and Conservation NSW has done one of the few long-term Australian studies on animal movement. He tracked the distribution of kangaroos and wild horses for 30 years during the 70s, 80s and 90s, and found these animals had all penetrated to higher altitudes, at the same time as the local climate has warmed slightly. These grazing animals have put pressure on the fragile alpine areas.

Green's research has also showed that seven out of 11 species of migratory birds that fly to the Alps annually arrived earlier in the year in the 1980s compared with the 1970s. Predictions are that a modest warming of 0.6 deg C by 2070 will result in a 39 per cent reduction in the area that receives 30 days of snow falls per year.

Queensland mountain-dwellers at risk

At the other end of the environmental extreme, Dr Stephen Williams from James Cook University has been looking at the impact of climate change on the World Heritage tropical rainforests of Queensland. He has found that animals such as frogs and lizards which live high up on the mountains are critically at risk. A spectacular lizard called Boyd's Forest Dragon, for example, would lose about 90 per cent of its suitable habitat by 2050, based on maximum climate warming scenarios.

Shifting climates

Examples abound of species shifting their annual cycles and going through strange changes. Fairy penguins are breeding earlier. Some eucalypts in Victoria are flowering a month later or earlier (depending on the species) than they did 20 years ago. Substantial areas of coral on the Great Barrier Reef were bleached and killed several years ago by unseasonably warm water temperatures.

Although Australian studies are few, Lesley Hughes believes it is time to take what we do know, add it to the hundreds of studies which have been done overseas and look at the overall picture. "I think the research as a whole is pointing in the same direction — which is saying that it's climate change. There's no question the climate has changed. It's how that is affecting the species and the biological impact that is more difficult to nail down."

Still, there will be winners and losers, says Lesley Hughes. "It's not disastrous for everything. The things that will do well are those species that are mobile and adaptable, such as weeds. Things that won't do well are those in isolated areas or specific climates, such as the top of a mountain in a tropical rainforest."

What's being done?

Reducing greenhouse gas emissions is critical. But given that the temperature is already rising and projected to keep going up, what can be done?

Scientists say long term studies are urgently needed to see what impact climate change is having. These could take the form of new research, closer study of existing databases, and increased community participation. Macquarie University, for example, has set up Biowatch. This is a public access database where anyone can report on changes and trends in species.

In 2003, the National Resource Management Ministerial Council launched the National Biodiversity and Climate Change Action Plan 2004-2007. The idea of this plan is to coordinate the efforts of all states and territories in dealing with the impact of climate change on biodiversity. Many researchers are urging that considerations of the impact of climate change be included in threatened species management plans and environmental impact assessments.

Others are taking a bolder view. The Wilderness Society has launched a campaign called WildCountry. The idea is to develop a large-scale continent-wide approach to conservation planning. The intention is to move far beyond national parks and nature reserves and incorporate land of all tenures into an overall conservation objective. This would go a long way towards linking up currently isolated pieces of land and forest, enabling species to migrate as the climate changed.

Seeing the landscape as an integrated whole, rather than as a system of locked off tenured land may in the end give Australia's biodiversity its best chance of surviving the next century.